The invention relates to a device for producing granulate from meltable compounds.
Such a device typically comprises an inner cylindrical drum at least one end of which is mounted stationarily to a support, and is fed internally with the compound to be granulated. The inner drum is provided with at least one downwardly directed row of openings. A cylindrical outer drum rests on the circumference of the inner drum so as to rotate in anti-friction bearings. The outer drum is provided with openings distributed over its entire circumference and which are brought cyclically into alignment with the openings of the inner drum. An axial seal is provided between the ends of the rotating outer drum and the stationary parts which retain the bearings.
Such a device is known for implementing the so-called rotoforming process (see prospectus of the Sandvik rotoforming process of the Sandvik Process Systems GmbH in 7012 Fellbach, Imprint: PS 500 GER 3.921). In these prior art designs an end flange of the outer drum is connected to a bearing ring against rotation relative thereto, which serves to brace the anti-friction bearing, whose inner race is connected rigidly to a stationary inner drum. An axial seal between the flange of the outer drum and the stationary inner bearing member is obtained by means of a first sealing ring connected to the flange of the outer drum, and a second sealing ring which interacts with the first sealing ring and is attached to the stationary bearing body. The second sealing ring is pressed axially by means of a set of cup springs against the first sealing ring. In these designs it can happen that product compounds, in particular if they have relatively low viscosity, can leak past the space between the stationary inner drum and the rotating outer drum at leaky points of the seal and flow into the region of the bearing, and can solidify there and lead to a malfunction, possibly even to intermittent stoppage of the production.